The invention relates to a pump capable of a range of industrial uses. The pump is of particular value in the pumping of nutrient liquid to feed a culture of micro-organisms and so will be described in relation to that use, but by way of illustration only. The pump can however be used on other applications, e.g. in medical equipment.
A pump can comprise a generally cylindrical stator containing an elongate rotor with spaced apart radial, flexible vanes disposed thereabout, as previously disclosed in British Patent No. 649814 to the H. J. Rand Washing Machine Corporation, British Patent No. 672522 to Mayus and See and in British Patent No. 1061278 to the Jabsco Pump Company.
The instant invention is based on the realisation that a pump comprising a generally cylindrical stator containing an elongate rotor can be improved if the flexible vanes are present in the clearance between the rotor and the stator and that they are disposed on either the stator or the rotor in a helical fashion.
According to the invention in one aspect there is provided a pump comprising a stator having a generally cylindrical bore which contains a rotor, one of the stator and the rotor containing radially spaced apart vanes and the other of the stator and rotor having at least one radial deformation, the vanes being flexible and extending in a generally helical manner from one end of the shaft or the rotor towards the other and the deformation being disposed and arranged to flex the vanes when they meet the deformation.
According to the invention in a specific aspect there is provided a pump comprising a stator and a rotor, the stator having a generally cylindrical bore in which is disposed the rotor, the rotor carrying spaced apart radial vanes and the stator having at least one radial deformation, the vanes being flexible and extending in a generally helical manner from one end of the rotor towards the other and the deformation being disposed and adapted to flex the vanes when they meet the deformation. I have also described and claimed a method of using the pump.
It is possible to reverse the location of the co-operating vanes and cam deformation surfaces within the pump.
In another specific aspect therefore the invention provides a pump comprising a stator and a rotor, the stator having a generally cylindrical bore, on an inner surface of which there is mounted spaced apart radial vanes, the rotor being disposed within said bore and having at least one radial deformation, the vanes being flexible and extending in a generally helical manner from one end of the stator towards the other and the deformation being disposed and adapted to flex the vanes when they meet the deformation.
The number of deformations may be varied. If a number of such surfaces is substantially evenly distributed about the major axis of the stator the rotor will be centred.
The vanes may be made of any suitable natural synthetic material, typically a plastics, including where appropriate a biopolymer. They make take any suitable shape and preferably comprising a thin vertical web having an enlarged head. The design of the vanes will be related to the deformation surface(s) which act as a cam to flex the vanes as they go past the deformation.
The pump may be connected to or be incorporated in a prime mover, for example, an electromagnetic drive system. The pump may be used for liquids or gases and may, for example, be used in association with a gas compressor.
A further aspect of the invention provides a bearing-free pump comprising a stator having an inlet and an outlet and being provided with at least one radial deformation, and a rotor carrying spaced apart radial vanes which extend in a generally helical manner from one end of the rotor toward the other, the vanes being adapted to flex on contact with said deformation, and wherein the rotor is moveable in response to a fluid-flow failure.
In another aspect the invention provides a method of pumping a fluid by rotation of a rotor in the generally cylindrical bore of a stator, one of the stator and the rotor carrying radially spaced apart flexible vanes and the other of the stator and the rotor at least one radial vane deflecting means, the vanes extending in a generally helical manner from one end of the stator towards the other, the method comprising rotating the rotor in the stator and flexing the vanes as they move past the vane deflecting means, whereby fluid between neighbouring vanes is caused to move along the rotor helically in addition to circumferentially.
In a specific aspect the invention provides a method of pumping a fluid by rotation of a rotor in the generally cylindrical bore of a stator, the rotor carrying spaced apart radial flexible vanes and the stator being provided with at least one radial deformation, the vanes extending in a generally helical manner from one end of the rotor towards the other, the method comprising rotating the rotor in the stator and flexing the vanes as they move past one deformation, whereby fluid between neighbouring vanes is caused to move along the rotor helically in addition to circumferentially.
In another aspect the invention provides a method of pumping a fluid by rotation of a rotor in the generally cylindrical bore of a stator, the stator carrying spaced apart radial flexible vanes and the rotor being provided with at least one radial deformation, the vanes extending in a generally helical manner from one end of the stator towards the other, the method comprising rotating the rotor in the stator and flexing the vanes as they move past one deformation, whereby fluid between neighbouring vanes is caused to move along the rotor helically in addition to circumferentially.
A pump of the invention may be used to transport liquids such as blood or stiff slurries, e.g. cement based slurries, or in a multistage bore pump in, e.g. oil wells. If any solid particles become trapped between the vanes and the inner surface of the stator the vanes will flex so allowing the pump to continue operating, especially when a number of cam surfaces is present.
Other features of the invention are set out in the dependent claims.